The present invention is related to an actuating apparatus for a disc brake.
One known actuating apparatus is shown in the German published patent application No. 2,448,182 C2. In that actuating apparatus, the axis of the actuating shaft is positioned parallel to the axis of the piston. The actuating shaft is provided with a crank jogged radially relative to the axis of the actuating shaft, in which crank there is a recess to support one end of a thrust member. In the hollow piston of that actuating apparatus, there is arranged a pressure device which is comprised of an external sleeve, an internal pin coupled to the piston and a locking mechanism between the pin and piston and the sleeve. The connection of the sleeve to the pin by means of the locking mechanism allows an automatic adjustment of the overall length of said pressure device. In its center, the end of the sleeve facing the front wall of the cylinder is furnished with a recess which accommodates the other end of the thrust member. Outside the cylinder, the actuating shaft has a polygonal cross-section at which an operating lever is received. Said lever is retained in its position in axial direction by a nut and a lock washer and is urged by a torsion spring into a first swivelling position in which the lateral jogging between the recesses receiving the thrust member is at its maximum. By a swivelling motion of the lever against the force of the torsion spring, the lateral jogging between the recesses is reduced and thereby the inclination of the thrust member diminished, as a result whereof the pressure device is urged away from the cylinder front wall in order to adjust the piston mechanically. Such an actuating apparatus is very expensive to manufacture and mount in a vehicle. In particular, an exact adjustment of the actuating shaft in an axial direction is very difficult, if not altogether impossible, since the operating lever is abutted against a flexibly yielding seal which is located in the cylinder front wall. This may lead to inconvenience in operation because the axial position of the thrust member fails to be exactly defined.
Accordingly, it is seen that actuating apparatuses are already in use in which the actuating shaft extends vertically to the direction of motion of the piston and is supported excentrically in order to impart to the thrust member an axially directed motional component. Nevertheless, the axial position of the actuating shaft and, consequently, of the thrust member taking support on it fails to be distinctly defined in these arrangements.
The present invention has, therefore, an object to provide an actuating apparatus which is easy to set-up and mount, and in which no inconveniences arise from not being able to exactly define the axial position of the thrust member.